fix(date-picker): remove duplicate call to onChangeCalback #6067 (#6131)

Author: PlamenaMiteva

projects/igniteui-angular/src/lib/date-picker/date-picker.component.ts

@@ -953,7 +953,6 @@ export class IgxDatePickerComponent implements IDatePicker, ControlValueAccessor
 
         this.emitValueChangeEvent(oldValue, this.value );
         this.onSelection.emit(date);
-        this._onChangeCallback(date);
     }
 
     /**
@@ -974,7 +973,6 @@ export class IgxDatePickerComponent implements IDatePicker, ControlValueAccessor
         if (this.calendar) {
             this.calendar.deselectDate();
         }
-        this._onChangeCallback(null);
     }
 
     /**
@@ -1060,7 +1058,6 @@ export class IgxDatePickerComponent implements IDatePicker, ControlValueAccessor
 
         this.emitValueChangeEvent(oldValue, this.value );
         this.calendar.viewDate = date;
-        this._onChangeCallback(date);
         this.closeCalendar();
         this.onSelection.emit(date);
     }
@@ -1205,7 +1202,6 @@ export class IgxDatePickerComponent implements IDatePicker, ControlValueAccessor
 
                         this.emitValueChangeEvent(oldValue, this.value );
                         this.invalidDate = '';
-                        this._onChangeCallback(newValue);
                 } else {
                     const args: IDatePickerDisabledDateEventArgs = {
                         datePicker: this,